The objective of the proposed research is to acquire a better understanding of one aspect of children's social development, the process through which school children make and keep friends. The specific goal is to determine how characteristcs of individual children, such as age, race, sex and academic achievement and organizational characteristics of schools, such as grouping practices and the racial composition of the school, affect changes in children's friendship choices. To study the friendship process we will collect longitudinal data, including sociometric choices, on fourth, fifth and sixth grade children in six schools which vary in racial composition and organizational structure. A stochastic model of the friendship process will be employed in analyzing the data. The results will help researchers and educators understand who school children choose as friends and how school and classroom practices affect these friendship choices.